41
Tertiary Phonolite (three samples):
o
ANP values range from 6 to 20 TCaCO
3
/kT
o
AGP values range from 0.2 to 1.25 TCaCO
3
/kT
o
NPR values range from 4.8 to 70.4. All samples fall into the NPAG category.
o
NNP values range from 4.8 to 19.1 TCaCO
3
/kT. All samples fall into the
Uncertain category.
o
Paste pH values range from 7.6 to 8.1
o
NAG pH values range from 7.5 to 7.7 (all three samples)
Breccia (32 samples):
o
ANP values range from <DL to 292 TCaCO
3
/kT
o
AGP values range from 0.2 to 4.1 TCaCO
3
/kT
o
NPR values range from 0.5 to 633.6. Two samples are classified as PAG, two as
Uncertain, and 28 as NPAG.
o
NNP values range from -1.9 to 290.4 TCaCO
3
/kT. Twenty-two samples are
classified as Uncertain, ten as NPAG.
o
Paste pH values range from 6.6 to 8.8
o
NAG pH values range from 7.2 to 8.6 (six samples)
Clearly, neither the NNP nor NPR criteria indicate that there are many potentially acid
generating (PAG) samples (0% by NNP, 5% by NPR). Rather, the majority of samples are
classified as ‘Uncertain’ (78% by NNP, 6% by NPR) or NPAG (22% by NNP, 89% by NPR). The
numbers indicate a general dearth of AGP for the mostly oxidized waste material while pockets
of high ANP material exist, especially within the breccia lithology. Similarly, paste pH values are
circum-neutral, indicating that none of the samples are currently actively acid generating. NAG
pH values represent a conservative, long-term prediction of effluent pH, as the tests oxidize all
sulfides present in a sample. The results indicate that long-term pH values will also be circum-
neutral, consistent with the NNP and NPR classifications.
SPLP and NAG short-term leach tests can be summarized for the four lithologies as follows:
Overburden (one sample):
o
SPLP effluent: Wyoming groundwater standards (Class 1 Domestic) exceeded
for iron and manganese
o
NAG effluent: Wyoming groundwater standards (Class 1 Domestic) exceeded for
manganese
Tonalite Trachyte Porphyry (ten samples):
o
SPLP effluent: Wyoming groundwater standards (Class 1 Domestic) exceeded
for iron and manganese (two samples)
o
NAG effluent: Wyoming surface water standards exceeded for arsenic (two
samples) and Wyoming groundwater standards (Class 1 Domestic) exceeded for
manganese (three samples)
Tertiary Phonolite (three samples):
o
SPLP effluent: All water quality standards met
